Protection of digital data from unauthorized access has been a primary concern of software vendors from the time software vendors first began delivering computer software on portable data storage media. Such protection has taken on new significance since other forms of digital data are now also transported on portable data storage media. For example, current personal computers read and write data storage media that is also used for ubiquitous audiovisual entertainment such as audio compact discs (CDs) and digital video discs (DVDs). Thus, common personal computers are capable of replicating very valuable data such that exact copies of the original data can easily be distributed to acquaintances.
One recent development has greatly expanded the threat to commercial value of easily copyable digital data: the Internet. Now, individuals can, and frequently do, post valuable digital data for free copying by millions of people. Such posting represents a catastrophic failure of any attempts to prevent unauthorized copying.
One early attempt at preventing unauthorized copying of software was to require a hardware device to be attached to a computer for the software to execute. Such devices were commonly referred to as “dongles.” A dongle either included identification data checked by the software prior to execution or included encryption data and/or logic to decrypt software prior to execution. Dongles were typically externally attachable such that software could be transferred to another computer by attaching the dongle to the other computer.
Dongles never realized much success in the marketplace. One reason is that multiple software products can be installed in each computer. As a result, many dongles would have to be attached to each computer. Another reason is that adding a new hardware device to a computer could have unintended results, interfering with the normal operation of the computer. A third reason is that many people have multiple computers and moving one of multiple dongles from one computer to another on a regular basis was a significant inconvenience. In general, users preferred not to attach new hardware to their computers to run software if a competing software vendor did not require such additional hardware.
Machine binding, for example, by use of dongles, is generally unacceptable to people purchasing audiovisual content rather than computer software. Perhaps as a result of the portable nature of historical distribution media of audiovisual content (e.g., vinyl albums, audio CDs; video tape, DVDs, etc.), the consuming public seems to expect that audiovisual content is permitted to be played on any devices owned by the purchaser. For example, a purchaser of a video cassette tape of a particular movie expects to be able to view the movie on any video cassette player of a compatible format. Thus, strict machine binding of audiovisual content is generally unacceptable by the consuming public.
Another mechanism by which software vendors attempt to thwart unauthorized copying of software is binding the software to a specific user. For example, successful execution of the software can be made contingent upon entering a password by the specific user. Such generally provides insufficient security since the user can communicate the password to a friend or associate along with an unauthorized copy of the software. In addition, requiring a user to remember passwords for each software product and/or each audiovisual work accessed by the user represents a considerable inconvenience to the user.
In general, it should be remembered that copy protection benefits the vendor of digital data, e.g., software and/or audiovisual works, and does not benefit the purchaser. Accordingly, purchasers of such digital data have a relatively low tolerance for inconvenience. As a result, the consuming public tends to purchase data from vendors employing less copy protection.
What is needed is a mechanism by which copyrightable content of digital storage media is protected against unauthorized copying while affording the owner of such digital storage reasonable unimpeded convenience of use and enjoyment of the content.